Stockholders' Equity Tax Benefit (Expense) on Net Activity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax Benefit (Expense)	$ (2)	$ 36	$ (1)	$ 26
Pension Plan
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax Benefit (Expense)	1	11	(3)	4
Other Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax Benefit (Expense)	0	29	0	29
Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax Benefit (Expense)	$ (3)	$ (4)	$ 2	$ (7)